Objectives: Communication requires cognitive processes which are not captured by traditional speech understanding tests. Under challenging listening situations, more working memory resources are needed to process speech, leaving fewer resources available for storage. The aim of the current study was to investigate the effect of task difficulty predictability, that is, knowing versus not knowing task difficulty in advance, and the effect of noise reduction on working memory resource allocation to processing and storage of speech heard in background noise. For this purpose, an “offline” behavioral measure, the Sentence-Final Word Identification and Recall (SWIR) test, and an “online” physiological measure, pupillometry, were combined. Moreover, the outcomes of the two measures were compared to investigate whether they reflect the same processes related to resource allocation. Design: Twenty-four experienced hearing aid users with moderate to moderately severe hearing loss participated in this study. The SWIR test and pupillometry were measured simultaneously with noise reduction in the test hearing aids activated and deactivated in a background noise composed of four-talker babble. The task of the SWIR test is to listen to lists of sentences, repeat the last word immediately after each sentence and recall the repeated words when the list is finished. The sentence baseline dilation, which is defined as the mean pupil dilation before each sentence, and task-evoked peak pupil dilation (PPD) were analyzed over the course of the lists. The task difficulty predictability was manipulated by including lists of three, five, and seven sentences. The test was conducted over two sessions, one during which the participants were informed about list length before each list (predictable task difficulty) and one during which they were not (unpredictable task difficulty). Results: The sentence baseline dilation was higher when task difficulty was unpredictable compared to predictable, except at the start of the list, where there was no difference. The PPD tended to be higher at the beginning of the list, this pattern being more prominent when task difficulty was unpredictable. Recall performance was better and sentence baseline dilation was higher when noise reduction was on, especially toward the end of longer lists. There was no effect of noise reduction on PPD. Conclusions: Task difficulty predictability did not have an effect on resource allocation, since recall performance was similar independently of whether task difficulty was predictable or unpredictable. The higher sentence baseline dilation when task difficulty was unpredictable likely reflected a difference in the recall strategy or higher degree of task engagement/alertness or arousal. Hence, pupillometry captured processes which the SWIR test does not capture. Noise reduction frees up resources to be used for storage of speech, which was reflected in the better recall performance and larger sentence baseline dilation toward the end of the list when noise reduction was on. Thus, both measures captured different temporal aspects of the same processes related to resource allocation with noise reduction on and off.

The aim of the current study was to investigate whether task-evoked pupillary responses measured during encoding, individual working memory capacity and noise reduction in hearing aids were associated with the likelihood of subsequently recalling an item in an auditory free recall test combined with pupillometry. Participants with mild to moderately severe symmetrical sensorineural hearing loss (n = 21) were included. The Sentence-final Word Identification and Recall (SWIR) test was administered in a background noise composed of sixteen talkers with noise reduction in hearing aids activated and deactivated. The task-evoked peak pupil dilation (PPD) was measured. The Reading Span (RS) test was used as a measure of individual working memory capacity. Larger PPD at a single trial level was significantly associated with higher likelihood of subsequently recalling a word, presumably reflecting the intensity of attention devoted during encoding. There was no clear evidence of a significant relationship between working memory capacity and subsequent memory recall, which may be attributed to the SWIR test and RS test being administered in different modalities, as well as differences in task characteristics. Noise reduction did not have a significant effect on subsequent memory recall. This may be due to the background noise not having a detrimental effect on attentional processing at the favorable signal-to-noise ratio levels at which the test was conducted.

Objectives: Visual and contextual cues facilitate speech recognition in suboptimal listening conditions (e.g., background noise, hearing loss, hearing aid signal processing). Moreover, successful speech recognition in challenging listening conditions is linked to cognitive abilities such as working memory and fluid intelligence. However, it is unclear which cognitive abilities facilitate the use of visual and contextual cues in individuals with normal hearing and hearing aid users. The first aim was to investigate whether individuals with hearing aid users rely on visual and contextual cues to a higher degree than individuals with normal hearing in a speech-in-noise recognition task. The second aim was to investigate whether working memory and fluid intelligence are associated with the use of visual and contextual cues in these groups. Design: Groups of participants with normal hearing and hearing aid users with bilateral, symmetrical mild to severe sensorineural hearing loss were included (n = 169 per group). The Samuelsson and Rönnberg task was administered to measure speech recognition in speech-shaped noise. The task consists of an equal number of sentences administered in the auditory and audiovisual modalities, as well as without and with contextual cues (visually presented word preceding the sentence, e.g.,: “Restaurant”). The signal to noise ratio was individually set to 1 dB below the level obtained for 50% correct speech recognition in the hearing-in-noise test administered in the auditory modality. The Reading Span test was used to measure working memory capacity and the Raven test was used to measure fluid intelligence. The data were analyzed using linear mixed-effects modeling. Results: Both groups exhibited significantly higher speech recognition performance when visual and contextual cues were available. Although the hearing aid users performed significantly worse compared to those with normal hearing in the auditory modality, both groups reached similar performance levels in the audiovisual modality. In addition, a significant positive relationship was found between the Raven test score and speech recognition performance only for the hearing aid users in the audiovisual modality. There was no significant relationship between Reading Span test score and performance. Conclusions: Both participants with normal hearing and hearing aid users benefitted from contextual cues, regardless of cognitive abilities. The hearing aid users relied on visual cues to compensate for the perceptual difficulties, reaching a similar performance level as the participants with normal hearing when visual cues were available, despite worse performance in the auditory modality. It is important to note that the hearing aid users who had higher fluid intelligence were able to capitalize on visual cues more successfully than those with poorer fluid intelligence, resulting in better speech-in-noise recognition performance.

Purpose: Although the existing literature has explored the link between cognitive functioning and speech recognition in noise, the specific role of fluid intelligence still needs to be studied. Given the established association between working memory capacity (WMC) and fluid intelligence and the predictive power of WMC for speech recognition in noise, we aimed to elucidate the mediating role of fluid intelligence. Method: We used data from the n200 study, a longitudinal investigation into aging, hearing ability, and cognitive functioning. We analyzed two age-matched samples: participants with hearing aids and a group with normal hearing. WMC was assessed using the Reading Span task, and fluid intelligence was measured with Raven's Progressive Matrices. Speech recognition in noise was evaluated using Hagerman sentences presented to target 80% speech-reception thresholds in four-talker babble. Data were analyzed using mediation analysis to examine fluid intelligence as a mediator between WMC and speech recognition in noise. Results: We found a partial mediating effect of fluid intelligence on the relationship between WMC and speech recognition in noise, and that hearing status did not moderate this effect. In other words, WMC and fluid intelligence were related, and fluid intelligence partially explained the influence of WMC on speech recognition in noise. Conclusions: This study shows the importance of fluid intelligence in speech recognition in noise, regardless of hearing status. Future research should use other advanced statistical techniques and explore various speech recognition tests and background maskers to deepen our understanding of the interplay between WMC and fluid intelligence in speech recognition.

Objective:In the present study, we investigated whether varying the task difficulty of the Sentence-Final Word Identification and Recall (SWIR) Test has an effect on the benefit of noise reduction, as well as whether task difficulty predictability affects recall. The relationship between working memory and recall was examined. Design:Task difficulty was manipulated by varying the list length with noise reduction on and off in competing speech and speech-shaped noise. Half of the participants were informed about list length in advance. Working memory capacity was measured using the Reading Span. Study sample:Thirty-two experienced hearing aid users with moderate sensorineural hearing loss. Results:Task difficulty did not affect the noise reduction benefit and task difficulty predictability did not affect recall. Participants may have employed a different recall strategy when task difficulty was unpredictable and noise reduction off. Reading Span scores positively correlated with the SWIR test. Noise reduction improved recall in competing speech. Conclusions:The SWIR test with varying list length is suitable for detecting the benefit of noise reduction. The correlation with working memory suggests that the SWIR test could be modified to be adaptive to individual cognitive capacity. The results on noise and noise reduction replicate previous findings.

Introduction Individuals with hearing loss and hearing aid users report higher levels of listening effort and fatigue in daily life compared with those with normal hearing. However, there is a lack of objective measures to evaluate these experiences in real-world settings. Recent studies have found that higher sound pressure levels (SPL) and lower signal-to-noise ratios (SNR) are linked to increased heart rate and decreased heart rate variability, reflecting the greater effort required to process auditory information. This study aims to establish physiological and acoustic predictors of self-reported listening effort and fatigue in daily life. Additionally, the moderating effects of cognitive abilities, personality traits, stress, fatigue, suprathreshold abilities, noise annoyance, lifestyle and health on the development of listening effort and fatigue will be investigated. Methods and analysis A 4-week field trial will be conducted, in which physiological responses will be continuously recorded using Empatica Embrace Plus wristbands. Ambient acoustics will be captured every 20 s via the participants’ (n=60) personal hearing aids, and the participants will provide self-reported momentary assessments through a mobile app throughout the day. Questionnaires will be used to assess personality traits, fatigue, stress and noise annoyance, and gather relevant background information. Cognitive and suprathreshold abilities will also be evaluated. Associations between physiological responses, ambient acoustics and momentary assessments, as well as the potential influence of participant characteristics, will be analysed using multilevel regression models and time-series analyses. Ethics and dissemination Informed consent will be obtained from all participants. The study has been exempted from ethical application by the Science Ethics Committee for the Capital Region of Denmark (journal no. F-23028367). Results will be presented at conferences and submitted for publication in peer-reviewed journals.